The open 9/9 problem

Does a 3×3 magic square of nine distinct perfect squares exist?

The required integral square must have nine positive, pairwise distinct perfect-square entries. Neither such a square nor a proof of its impossibility is currently known.

ABCDGa partial 5/9 case
A17689
B27889
C11449
D12769
E19009
F25249
G26569
H10129
J20329
E19 009x−1 320y7 560
5/9 squares

Approach to the problem

Partial configurations

Definitions

To separate the positional and arithmetic restrictions of the 9/9 problem, the study considers k/9 squares in which only selected entries are required to be squares. Classifications and parametrizations of these patterns do not solve the original problem, but describe its partial cases.

4/9complete classification

23 square-pattern orbits and their parametric families.

5/9complete classification

23 square-pattern orbits and general parametrization methods.

6/9work in progress

An atlas of positional types, tfmn classes, and individual elliptic surfaces.

9/9open problem

Neither the required square nor a proof of its impossibility is known.

Results arising from the investigation

Related results

The study of partial configurations led to independent results that are not limited to the 9/9 problem.

I

Square classes and congruent numbers

The functions f and tf, the exact relation between parameter pairs and the curves y²=x³−T²x, and the F4+, F7+, and F9+ methods.

III

Algebra of magic matrices

The five-dimensional algebra of semimagic squares, its decomposition, and its relation to split quaternions.

Site contents

Sections

I

Theory

A sequential account from the general form of a magic square to elliptic surfaces.

Contents
II

Pattern atlases

Orbits of square positions with equations, statuses, and links to derivations.

III

Computations

Calculators for parametric families, 6/9 patterns, and operations on magic squares.